5" square tube frame rails
My '53 Studebaker pick up has seen a lot of different drive trains and chassis over the last 40 years. I will now embark on the last and best chassis that I hope to build. I have a '97 T-bird IRS and will get a '03-'07 crown vic front susp. I'll be running a Ford 300" six with an AOD 4 speed auto. With 12" &10" discs, rack &pinion and all 4 wheels independent, the handling should be spectacular. The problem, of course, is that I will be using a ladder frame. I've seen a lot of frame articals and they look rather flimsy. 2x3 tube may be OK for a weekend roadster, but mine will be a daily driver and will compete with today's machines. I'm thinking of using 5" square tube .125 wall. Mainly because I already have some. With some well placed crossmembers it should have good torsional stiffness. Being only .125 wall, I calculate that it should weigh around 350#. I don't know how that compares in the frame world, but it didn't seem that heavy to me.
Just looking for some feedback and if there is some glaring no-no that I may be missing.